1. Field of the Invention
The invention relates generally to filter screen assemblies for use with such as large sized air intake/handling units. More specifically, the present invention teaches the incorporation of a stand-off structure, such as a perimeter extending stand-off frame or perimeter secured spacing collars, in either instance spacing a filter mesh media away from a surface of an air intake structure, in order to prevent the incidence of hail damage to surface coils associated with the structure. Spacing of the filter mesh from adhering contact with the air intake coils further allows its heavy duty and vinyl coated polyester medium to function in a drum-like manner to absorb and deflect the forces associated with the hail or other foreign objects impacting the filter at varying angles and without damaging the underlying surface structure associated with the air handling unit.
2. Description of the Prior Art
The prior art is well documented with examples of filter assemblies, and in particular those in use with air intake structures. The objective in such instances is to provide an effective screen covering for a structural air intake, and such as in particular a cooling tower or other similar industrial based structure.
A first example drawn from the prior art is disclosed in U.S. Pat. No. 5,370,722, issued to Simmons, which teaches a filtering assembly for protecting an air intake of a structure and including a flexible screen mounted so as to cover the air intake. The screen is selectively moved in either of opposite directions, such as through application of first and second pulley assemblies located on opposite sides of the screen which are engaged by pull ropes to raise and lower the screen. A container is located at a base of the structure, beneath the intake opening, and stores the flexible screen when not in use.
In a second preferred embodiment, first and second containers are secured to the structure at locations above and below the intake opening. The flexible screen is formed as first and second interconnected and cylindrical rolls placeable within the containers and operable by a crank to advance an intermediate, unrolled and interconnected portion of the screen across the intake opening.
A further example of the prior art is disclosed in U.S. Pat. No. 6,197,077, also issued to Simmons, and disclosing a filter screen assembly mounted over an air intake structure having a height, width and depth and which defines a selected face within which the air intake opening is formed. A planar and flexible filtration screen defines a substantially rectangular shape with top, bottom and first and second side edges. Fasteners are provided for securing the sides of the screen to corresponding sides of the intake structure and include eyelets formed within the screen which are supported upon tubular portions extending from the structure and fasteners which secure within the tubular portions to affix the screen in place.
In a preferred embodiment, a stiffening and engaging bar associated with a top edge of the flexible screen includes upwardly extending hooks 36 and 38 which are secured upon an engaging bar mounted in extending fashion along a top edge of the structure. A side extending engagement of the screen is facilitated by collars secured to the edges of the air intake structure and to which eyelets formed along the screen edges are aligned and secured thereover through the further addition of screws or the like.
U.S. Pat. No. 6,279,335, issued to Jacobs, teaches a refrigerated case cover having a cover sheet constructed of an insulating material and having air cells sandwiched between an outer cover sheet and an inner cover sheet. Eyelets are disposed along the top and bottom edges of the cover and a cord is woven through the lower eyelets. A male tab is disposed on each cover sheet side and the cover is attached to a refrigerated case by attaching the upper eyelets to an upper case front lip by means of S hooks, and attaching the cord to grille spokes disposed along a lower case front upper edge with S hooks, and by attaching each cover sheet side to a respective case side with hook-and-loop material. In an alternate embodiment, a refrigerated case cover has weights disposed along the cover sheet lower edge in order to keep the refrigerated case cover sealed against a refrigerated case lower front, and to expedite installation and removal of the refrigerated case cover.